CN103079272A - Communication control apparatus and control method thereof, communication apparatus and control method thereof, and wireless communication system - Google Patents

Abstract

A communication control apparatus that performs wireless communication with a plurality of communication apparatuses, the communication control apparatus comprises: a grouping unit adapted to group the plurality of communication apparatuses based on the relative positions of each of the plurality of communication apparatuses; a notification unit adapted to notify each of the plurality of communication apparatuses of the group to which that communication apparatus belongs and of a communication slot allocated to that group; and a transmission unit adapted to transmit transmission data at a predetermined timing.

Description

Communication control device, communication device and control method thereof, wireless communication system

(This application is a divisional application of the application dated November 16, 2007, the application number is 200710187122.6, and the title of the invention is "communication control equipment and communication equipment and its control method, wireless communication system")

technical field

The invention relates to a communication control device and its control method, a communication device and its control method and a wireless communication system.

Background technique

A technique is known for the purpose of configuring a plurality of connection links through relay transmission using a telecommunication terminal and performing wireless transmission (Japanese Patent Laid-Open No. 8-97821; Japanese Patent Laid-Open No. 2001-189971). Specifically, there is known a wireless communication system in which address information, relay information, etc. are added to communication data and transmitted to a plurality of addresses, and a relay terminal Wait to relay the data.

In addition, there is known a wireless communication scheme whose object is to extend the communication range of a receiving terminal by transmitting the same data from a plurality of transmitters (Japanese Patent Laid-Open No. Hei 11-122150). Specifically, a scheme is known: multiple transmission signals to which different delays have been added are transmitted from multiple transmission terminals; at the receiving end, the received undisturbed signal is selected and equalized to estimate the Raw data.

In addition, as a technology for efficiently transmitting data to remote communication terminals in a wireless manner, a scheme is known in which a relay terminal having good communication conditions is selected and data is distributed to peripheral communication terminals through the relay terminal, thereby achieving efficient Data transmission (Japanese Patent Laid-Open No. 2003-332977).

However, in recent years, data communication functions have been widely used, and the demand for so-called "real-time" communication in which video data, audio data, etc. , audio reproduction device, etc. to receive and reproduce these data.

A scheme such as the conventional scheme described above responds to the occurrence of disconnections and interruptions in the communication path caused by some kind of problem in the communication path by performing retransmissions, changing paths, and the like. However, retransmission processing, processing for changing paths, and the like are performed asynchronously, so transmission delay cannot be guaranteed. Therefore, when temporally continuous stream data such as video or audio is transmitted and continuously reproduced at the receiving end, and a disconnection or interruption occurs in the communication path, a data underrun occurs at the receiving end. Therefore, there are problems that reproduced video is unstable, reproduced audio stops intermittently, and the like.

In the conventional scheme described above, by using a plurality of paths, reception can be correctly performed even if a disconnection or interruption occurs in a single path. However, these processes assume a predetermined plurality of transmission terminals and a single reception terminal, and merely realize connection of multiple paths by eliminating signal interference from a plurality of transmission terminals. Therefore, when data transmission is performed uniformly to a plurality of receiving terminals, such as with multi-channel stream data, mutual interference occurs when data is transmitted to the respective receiving terminals over a plurality of paths.

Contents of the invention

In consideration of the above-mentioned problems, an object of the present invention is to provide a technique for reducing the occurrence of disconnections and interruptions in transmitting data such as time-continuous streaming data such as video and audio. It is also an object of the present invention to provide a technique for avoiding mutual interference even when a plurality of pieces of data are simultaneously transmitted to a plurality of reception terminals.

According to one aspect of the present invention, a communication control device for performing wireless communication with a plurality of communication devices, the communication control device includes:

a grouping unit for grouping the plurality of communication devices based on a relative location of each of the plurality of communication devices;

a notification unit for notifying each of the plurality of communication devices of a group to which the communication device belongs and a communication slot allocated to the group; and

The transmission unit is configured to transmit transmission data according to a predetermined timing.

According to another aspect of the present invention, a communication device for performing wireless communication in a wireless communication system including a communication control device and a plurality of communication devices, the communication device includes:

a notification receiving unit configured to receive, from the communication control device, a notification of a group to which the communication device belongs and a communication slot allocated to the group;

a data receiving unit, configured to receive transmission data from an external device, and store the received data in a storage device;

a maximum likelihood processing unit configured to perform maximum likelihood processing on the transmission data stored in the storage device; and

A transmission unit for transmitting the transmission data on which the maximum likelihood processing has been performed using the communication slot allocated to the group to which the communication device belongs.

According to still another aspect of the present invention, a wireless communication system including a communication control device and a plurality of communication devices,

Wherein, the communication control device includes:

a grouping unit for grouping the plurality of communication devices based on the relative location of each of the plurality of communication devices;

a notification unit for notifying each of the plurality of communication devices of a group to which the communication device belongs and a communication slot allocated to the group; and

a transmission unit, configured to transmit transmission data according to predetermined timing, and

Each of the communication devices includes:

a notification receiving unit configured to receive, from the communication control device, a notification of a group to which the communication device belongs and a communication slot allocated to the group;

a data receiving unit, configured to receive transmission data from an external device, and store the received data in a storage device;

a maximum likelihood processing unit configured to perform maximum likelihood processing on the transmission data stored in the storage device; and

A transmission unit for transmitting the transmission data on which the maximum likelihood processing has been performed using a communication slot allocated to a group to which the communication device belongs.

According to still another aspect of the present invention, a control method for a communication control device, where the communication control device performs wireless communication with a plurality of communication devices, the method includes:

grouping the plurality of communication devices based on a relative location of each of the plurality of communication devices;

notifying each of the plurality of communication devices of the group to which the communication device belongs and the communication slots assigned to the group; and

Transmission data is transmitted according to predetermined timing.

According to still another aspect of the present invention, a control method for a communication device that performs wireless communication in a wireless communication system including a communication control device and a plurality of communication devices, the method includes:

receiving a notification of a group to which the communication device belongs and a communication slot allocated to the group from the communication control device;

receiving transmission data from an external device, and storing the received data in a storage device;

performing maximum likelihood processing on said transmission data stored in said storage means; and

The transmission data that has been subjected to the maximum likelihood processing is transmitted using the communication slot allocated to the group to which the communication device belongs.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the accompanying drawings).

Description of drawings

FIG. 1 is a diagram showing an example of the configuration of a network including wireless communication devices.

FIG. 2 is a block diagram showing an internal configuration of a control terminal.

Fig. 3 is a block diagram showing the internal configuration of a node.

FIG. 4 is a diagram schematically showing a difference in signal transmission range between DSSS and OFDM techniques.

FIG. 5 is a diagram showing a detailed configuration of a wireless transmission unit and a wireless reception unit of a control terminal.

FIG. 6 is a diagram showing a detailed configuration of a wireless transmission unit and a wireless reception unit of a node.

Fig. 7 is a flowchart showing the operation procedure performed by the control terminal.

8A and 8B are time slot diagrams illustrating operations of a control terminal.

FIG. 9 is a flowchart showing the processing procedure performed by each node.

10A, 10B, 10C, and 10D are diagrams conceptually showing changes over time in streaming data transmission by control terminals and nodes.

FIG. 11 is a diagram showing streaming data transmission by a control terminal and nodes on a time axis.

FIG. 12 is a diagram showing the procedure of node topology determination processing by the control terminal and by the nodes.

Fig. 13 is a graph schematically showing the relationship between the strength of the received training signal and the distance between nodes.

FIG. 14 is a diagram schematically illustrating estimation of a positional relationship using triangulation.

Fig. 15 is a diagram schematically showing the configuration of a network when a single group exists.

FIG. 16 is a diagram schematically showing the configuration of a network when two groups exist.

FIG. 17 is a flowchart showing a processing procedure performed by the control terminal to determine a group and a time slot.

FIG. 18 is a diagram showing, on the time axis, streaming data transmission by a control terminal and a node in a case where control information has been added to a beacon signal.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the constituent elements shown in the following embodiments are merely examples, and the scope of the present invention is not limited thereto.

Example 1

Network Configuration

FIG. 1 is a diagram showing an example of the configuration of a network including wireless communication devices according to the present embodiment. In FIG. 1, 101-109 are nodes (communication devices) a to i, which are wireless communication devices according to this embodiment; 110 is a control terminal (communication control device), which is a wireless communication device; and 111 is an output AV A data source for (audio-visual) data. 112 is group 1 consisting of nodes a to c; 113 is group 2 consisting of nodes d to f; 114 is group 3 consisting of nodes g to i.

The data source 111 is a device that outputs AV data to be processed in real time. The data source 111 continuously outputs AV data such as multi-screen video data, multi-channel audio data, and the like.

The control terminal 110 exchanges control signals, control data, etc. with the nodes a 101 to i 109 in a wireless manner. Furthermore, the control terminal 110 converts AV data from the data source 111 into streaming data, and wirelessly transmits the streaming data.

Nodes a 101 to i 109 exchange control signals, control data, etc. with the control terminal 110 in a wireless manner. Furthermore, the nodes a 101 to i 109 wirelessly receive streaming data from the control terminal 110 and from a plurality of other nodes, and wirelessly transmit the received streaming data.

Group 1 ( 112 ) to Group 3 ( 114 ) are groups composed of a plurality of nodes. The group allocation is determined by the control terminal 110 and is notified to each node by control data. As will be described later, nodes within the same group all wirelessly transmit streaming data according to the same timing.

control terminal

FIG. 2 is a block diagram showing the internal configuration of the control terminal 110 . In FIG. 2, 201 is a wireless transmission unit, 202 is a wireless reception unit, 203 is a control unit that controls the overall operation of the control terminal 110, 204 is an encoding unit, 205 is a memory, 206 is a cycle timer, and 207 is an antenna.

The control unit 203 transmits control data to the wireless transmission unit 201 via the memory 205 , and controls the wireless transmission unit 201 to modulate the control data into a wireless signal and wirelessly transmit the generated wireless signal from the antenna 207 . In addition, AV data from the data source 111 is converted into stream data by the encoding unit 204 and temporarily stored in the memory 205 . Then, according to an instruction from the control unit 203, and in synchronization with the cycle timer 206, the control terminal 110 converts the streaming data into frames, that is, data transmission units, and transmits the generated frames from the memory 205 to the wireless transmission Unit 201. Thereafter, according to an instruction from the control unit 203 , and in synchronization with the cycle timer 206 , the wireless transmission unit 201 modulates the data from the memory 205 into a wireless signal, and then wirelessly transmits the generated wireless signal from the antenna 207 .

According to an instruction from the control unit 203 , the wireless receiving unit 202 receives a wireless signal from the antenna 207 , demodulates the wireless signal into received data, and transmits the received data to the control unit 203 . In addition to performing overall control, the control unit 203 writes a synchronization signal for controlling synchronization of wireless communication with other nodes into the memory 205, and controls such that the synchronization signal is transmitted from the wireless transmission unit 201 according to a prescribed timing. Furthermore, the control unit 203 converts the transmission data into frames according to terminal information communicated from other nodes as control data.

The wireless transmission unit 201 and the wireless reception unit 202 will be described in detail later. In this embodiment, the wireless transmission unit 201 of the control terminal 110 includes a DSSS modulation unit and an OFDM modulation unit. These two technologies adopt technologies conforming to IEEE 802.11 and IEEE 802.11a standardized by IEEE, so detailed descriptions thereof will be omitted. Note that "DSSS" is an abbreviation for "DirectSequence Spread Spectrum (Direct Sequence Spread Spectrum)", and "OFDM" is an abbreviation for "Orthogonal Frequency Division Multiplexing (Orthogonal Frequency Division Multiplexing)". "IEEE" is the abbreviation of "Institute of Electrical and Electronics Engineers (Institute of Electrical and Electronics Engineers)".

In addition, the wireless reception unit 202 of the control terminal 110 includes a DSSS type demodulation unit. When the stream data stored in the memory 205 is transmitted from the encoding unit 204, an OFDM type modulation unit is used. When transmitting and receiving other data, the DSSS type modulation unit and demodulation unit are used.

node

FIG. 3 is a block diagram showing the internal configuration of node a 101. Nodes b 102 to i109 have the same configuration. In other words, although the node a101 will be described below, these descriptions are equally applicable to the nodes b 102 to i 109. In Fig. 3, 301 is a wireless transmission unit, 302 is a wireless receiving unit, 303 is a control unit for controlling node operation, 304 is a memory, 305 is a maximum likelihood processing unit, 306 is a decoding unit, 307 is a cycle timer, and 308 is an antenna.

The wireless receiving unit 302 transmits to the wireless transmitting unit 301 a synchronization signal for notifying the symbol synchronization timing of received data. In addition, according to an instruction from the control unit 303 , and in synchronization with the cycle timer 307 , the wireless receiving unit 302 stores the received data in the memory 304 .

The control unit 303 selects data addressed to its own node from among received data stored in the memory 304 , and sends the data to the decoding unit 306 via the maximum likelihood processing unit 305 . The maximum likelihood processing unit 305 estimates maximum likelihood data from pieces of input data, and generates output data. The decoding unit 306 receives the maximum likelihood data from the maximum likelihood processing unit 305, decodes the received data, and outputs AV data. The AV data output from the decoding unit 306 is used in processing such as video reproduction and display, audio reproduction, and the like.

Furthermore, the control unit 303 transfers the pieces of received data stored in the memory 304 to the wireless transmission unit 301 via the maximum likelihood processing unit 305; the received data is wirelessly transmitted from the wireless transmission unit 301 in synchronization with the cycle timer 307 . Further, the control unit 303 transfers the terminal information of its own node to the wireless transmission unit 301 as control data to be communicated to the control terminal 110; the terminal information is wirelessly transmitted to the control terminal 110. The terminal information is the individual ID (identifier) value preset to identify the node itself, the capability information of the decoding unit 306, the capability information of the wireless receiving unit 302 and the wireless transmitting unit 301, and the like.

The wireless transmission unit 301 and the wireless receiving unit 302 of node a 101 include a DSSS type and OFDM type modulation unit and a demodulation unit. In the present embodiment, these two techniques adopt techniques conforming to IEEE 802.11 and IEEE 802.11a, and thus detailed description thereof will be omitted. Node a 101 uses the OFDM modulation unit for communication when transmitting streaming data, and uses the DSSS modulation unit for communication when transmitting other control data. In addition, node a 101 communicates using an OFDM demodulation unit when receiving stream data, and communicates using a DSSS demodulation unit when receiving other control data, control signals, and the like. The wireless transmission unit 301 and the wireless reception unit 302 will be described in detail later.

DSSS and OFDM technology

Next, the difference in characteristics between the DSSS used in this embodiment and the OFDM technique will be described.

The DSSS technology used by the control terminal 110 and nodes a 101 to i 109 is a modulation technology that directly spreads data with spreading codes using a differential binary phase shift keying (DBPSK) modulation technology. This can be realized with simple circuits, so it is a data communication technology capable of low-latency processing. When the transmission rate is lower than 1Mbps, the technology is highly error-resistant, and can correctly transmit data over long distances even in a communication environment with poor transmission conditions.

In addition, the OFDM technology in this embodiment adopts an advanced modulation technology called 64-position Quadrature Amplitude Modulation (64QAM) technology. Although this technique has a heavier processing load and higher latency than the DSSS technique, it is capable of a higher bit rate of 54 Mbps. However, the error resistance is lower than that of the DSSS technology, and the signal transmission range in which information can be correctly transmitted is smaller than that of the DSSS technology.

FIG. 4 is a diagram schematically showing a difference in signal transmission range between DSSS and OFDM techniques. In FIG. 4 , 401 schematically represents the concept of a distance for correct data transmission using the OFDM technology, and 402 schematically represents the concept of a distance for correct data transmission using the DSSS technology. In other words, FIG. 4 conceptually shows that the control terminal 110 and nodes a 101 to i 109 can use DSSS technology to perform data communication at a rate of 1 Mbps. In addition, FIG. 4 conceptually shows that the control terminal 110 and the nodes a 101 to c 103 and e 105 can use OFDM technology to perform data communication at a rate of 54 Mbps.

However, here, if a certain degree of error can be overcome, nodes outside the transmission range 401 can also perform data communication using OFDM technology. The probability of an error generally increases as the transmission distance increases. Forward Error Correction (FEC) codes are added to transmitted data frames for error correction at the receiving end. Therefore, due to error correction, if the transmission condition is good and the degree of error is small, even if the node is located outside the transmission range 401, the original data can be estimated; therefore, communication using OFDM technology can be used to perform correct data reception.

Although the above description discusses the case where the control terminal 110 transmits data, the above description is also applicable to the case where any one of nodes a 101 to i 109 uses OFDM technology to transmit data. In other words, OFDM technology can be used to perform 54Mbps communication between adjacent nodes, and DSSS technology can be used to perform 1Mbps communication between remote nodes and control terminals.

Wireless transmission unit/wireless reception unit of the control terminal

Next, the wireless transmission unit 201 and the wireless reception unit 202 of the control terminal 110 will be explained with reference to FIG. 5 . FIG. 5 is a diagram showing detailed configurations of the wireless transmission unit 201 and the wireless reception unit 202 of the control terminal 110 .

501 is a scrambling unit, which is used to randomize the bit string and reduce its correlation with irrelevant bit strings; 502 is a modulation unit for DBPSK modulation; and 503 is a spreading unit for spectrum spreading using spreading codes. The DSSS type modulation unit 521 is composed of a scrambling unit 501 , a modulation unit 502 and a spreading unit 503 .

504 is a convolutional encoding unit that performs redundant encoding for error correction processing. 505 is a modulation unit that divides input data among 48 subcarriers and performs 64-bit quadrature amplitude modulation (QAM). 506 is an inverse fast Fourier transform (IFFT) unit, which performs inverse fast Fourier transform on each modulated subcarrier signal. 507 is a guard interval (Guard Interval, GI) adding unit, which adds a guard interval for eliminating the influence of delayed interference waves. 508 is a shaping unit that performs waveform shaping to reduce out-of-band power. The OFDM type modulation unit 522 is composed of a convolutional encoding unit 504 , a modulation unit 505 , an IFFT unit 506 , a GI addition unit 507 , and a shaping unit 508 .

509 is a modulation unit for performing quadrature modulation on an intermediate frequency. 510 is a multiplier that converts the signal input from the modulation section 509 into a radio carrier frequency. 511 is a power amplifier (power amplifier, PA) for amplifying wireless transmission power.

Only one of the DSSS type modulation unit 521 and the OFDM type modulation unit 522 operates. In other words, the transmission data is processed by the scrambling unit 501 or the convolutional encoding unit 504 . Then, the processed data is output from the expansion unit 503 or the shaping unit 508 , and the data is input to the modulation unit 509 .

512 is an oscillator that generates an intermediate frequency, and 513 is an oscillator that generates a wireless carrier frequency. 514 is a low noise amplifier (low noise amplifier, LNA) that amplifies the received signal. 515 is a multiplier for extracting a signal tuned to the wireless carrier frequency. 516 is an automatic gain control (AGC) that automatically adjusts the signal strength to a predetermined amplitude strength. 517 is a detection unit that converts the signal frequency to an intermediate frequency and performs quadrature detection.

518 is a despreading unit, which multiplies the spread signal with the spread code to generate the original signal. 519 is a demodulation unit that generates original data from a DBPSK modulated signal. 520 is a descrambling processing unit to return the scrambled data to its original state. The DSSS type demodulation unit 523 is composed of a despreading unit 518 , a demodulation unit 519 and a descrambling processing unit 520 .

Wireless transmission unit/wireless reception unit of the node

FIG. 6 is a diagram showing detailed configurations of the wireless transmission unit 301 and the wireless reception unit 302 of the node a 101. The same diagram applies to nodes b 102 to i 109.

601 is a scrambling unit, which is used to randomize the bit string and reduce its correlation with irrelevant bit strings; 602 is a modulation unit for DBPSK modulation; and 603 is a spreading unit for spectrum spreading using spreading codes. The DSSS type modulation unit 629 is composed of a scrambling unit 601 , a modulation unit 602 and a spreading unit 603 .

604 is a convolutional coding unit that performs redundant coding for error correction processing. 605 is a modulation unit that divides input data among 48 subcarriers and performs 64QAM modulation. 606 is an IFFT unit, which performs inverse fast Fourier transform on each modulated sub-carrier signal. 607 is a GI adding unit which adds a guard interval for canceling the influence of delayed interference waves. 608 is a shaping unit that performs waveform shaping to reduce out-of-band power. The OFDM type modulation unit 630 is composed of a convolutional encoding unit 604 , a modulation unit 605 , an IFFT unit 606 , a GI addition unit 607 , and a shaping unit 608 . Also, modulating section 605 and GI adding section 607 perform symbol synchronization based on a synchronization signal from radio receiving section 302 .

609 is a modulation unit for performing quadrature modulation on an intermediate frequency. 610 is a multiplier that converts the signal to the radio carrier frequency. 611 is a PA that amplifies wireless transmission power.

Only one of the DSSS type modulation unit 629 and the OFDM type modulation unit 630 works. In other words, the transmission data is processed by the scrambling unit 601 or the convolutional encoding unit 604 . Then, the processed data is output by the expansion unit 603 or the shaping unit 608 and input to the modulation unit 609 .

612 is an oscillator that generates an intermediate frequency, and 613 is an oscillator that generates a wireless carrier frequency. 614 is an LNA that amplifies the received signal. 615 is a multiplier for extracting a signal tuned to the wireless carrier frequency. 616 is an automatic gain control (AGC) that automatically adjusts the signal strength to a predetermined amplitude strength. 617 is a detection unit that converts the signal frequency into an intermediate frequency and performs quadrature detection.

618 is a despreading unit, which multiplies the spread signal and the spread code to generate the original signal. 619 is a demodulation unit that generates original data from a DBPSK modulated signal. 620 is a descrambling processing unit to return the scrambled data to its original state. The DSSS type demodulation unit 632 is composed of a despreading unit 618 , a demodulation unit 619 and a descrambling processing unit 620 .

621 is an automatic frequency control (automatic frequency control, AFC) unit that corrects errors in the wireless carrier frequency. 622 is a GI removal unit for removing a guard interval added during transmission. 623 is a timing detection unit, which detects the frequency synchronization of the wireless carrier frequency, the frequency synchronization of the intermediate frequency, and the synchronization timing between frequency symbols according to the received signal. 624 is an FFT unit, which performs fast Fourier transform to divide the received data into each subcarrier. 625 is a channel estimation unit for estimating channel distortion of subcarrier signals, and 626 is an equalization unit for removing channel distortion from received data based on the estimation of channel distortion. In other words, the processing performed by channel estimation unit 625 and equalization unit 626 is maximum likelihood processing that estimates raw data from received data including multipath signals and the like. 627 is a demodulation unit that restores the original data of each subcarrier. 628 is a phase detection correction unit that detects the phase of each subcarrier and generates a correction signal, and 641 is a Viterbi (Viterbi) decoding unit that performs error correction on convolutionally encoded data and restores the original data. The OFDM type decoding unit 631 is composed of the functional processing units from the AFC unit 621 to the Viterbi decoding unit 641 .

The timing detection unit 623 and the phase detection correction unit 628 synchronize the detected timing with the synchronization cycle of the entire system, and maintain this synchronization; Work, and continuously generate periodic synchronization signals. The operations of the wireless transmission unit 301 and the wireless reception unit 302 are synchronized by supplying synchronization signals to the modulation unit 605 and the GI addition unit 607 of the wireless transmission unit 301 . In other words, an operation is performed such that the synchronization timing of the own node is synchronized with the synchronization timing of receiving data, and data is transmitted according to the synchronization timing. In this way, the nodes work in synchronization with each other, thereby establishing a synchronization of the entire communication network in which the nodes communicate with each other.

Control Terminal Operations

Next, the operation of the control terminal 110 will be explained with reference to FIGS. 7 , 8A, and 8B. FIG. 7 is a flowchart showing an operation procedure performed by the control terminal 110 . 8A and 8B are time slot diagrams illustrating operations of the control terminal 110. Referring to FIG.

In FIG. 7 , first, the control terminal detects a plurality of nodes existing in the surrounding area, and performs a process of determining the node topology (step S1 ) to determine the positional relationship between the nodes. Details of the node topology determination process will be provided later.

Next, according to the determined node topology, or in other words, according to the relative positions of the nodes, the time slot configuration and node group allocation for synchronous communication are determined, and the determined results are communicated by the wireless transmission unit 201 using DSSS technology to all nodes (step S2). In the case of the present embodiment, nodes a 101 to i 109 as shown in FIG. 1 are detected. Then, nodes are divided into groups 1 ( 112 ), 2 ( 113 ), and 3 ( 114 ), starting from the closer nodes outward, according to the positional relationship between the nodes and the control terminal 110 . Next, time slots are allocated as shown in FIG. 8A. 801 is the time interval Tf of the repetition period of the synchronous transmission. 802 is a shared slot that the control terminal 110 and nodes can use together, that is, slot 0, and its time interval is Tc. 803 is the slot in which the control terminal 110 can transmit, that is, slot 1. 804 is the slot in which the nodes of group 1 (112) can transmit, that is, slot 2. 805 is the slot in which the nodes of group 2 (113) can transmit , ie, slot 3. 806 is the slot in which nodes of group 3 (114) can transmit, ie, slot 4. The time intervals of slots 1 to 4 are all the same Ts.

Next, according to the time slot configuration, the cycle timer 206 starts counting operation with the cycle Tf of the time division communication (step S3 ). When the cycle timer 206 reaches the start time of the synchronization cycle Tf (YES in step S4 ), the process proceeds to step S5 .

In step S5 , as shown in 807 to 810 in FIG. 8A , the control terminal 110 transmits a beacon signal (beaconsignal) for notifying synchronization timing to all nodes. These beacon signals ( 807 , 808 , 809 , and 810 ) are transmitted by the wireless transmission unit 201 using DSSS technology capable of long-distance communication.

Next, the control terminal 110 judges whether there is control data to be transmitted through the shared slot, ie, slot 0 ( 802 ) (step S6 ). In the case where there is such control data ("Yes" in step S6), the process proceeds to step S7, and at the timing of slot 0 (802) indicated by the cycle timer 206, the waiting time is transmitted from the wireless transmission unit 201 using the DSSS technique. The transmitted control data. Then, the process goes to step S8. In a case where there is no control data ("No" in step S6), the process proceeds to step S8.

Further, the control terminal 110 judges whether there is control data to be received at the timing of the shared slot as indicated by the cycle timer 206 , that is, slot 0 ( 802 ) (step S8 ). In a case where there is control data to be received (YES in step S8), the process proceeds to step S9, and the control data is received by the wireless receiving unit 202 using the DSSS technique. Then, the process goes to step S10. In a case where there is no control data to be received ("No" in step S8), the process proceeds to step S10.

Next, the control terminal 110 judges whether there is stream data to be transmitted (step S10 ). In the case where there is such streaming data ("Yes" in step S10), the process proceeds to step S11, and in the case where there is no such streaming data ("No" in step S10), the process returns to step S4 and This process is repeated.

In step S11 , at the timing of slot 1 ( 803 ) indicated by the cycle timer 206 , the wireless transmission unit 201 performs transmission using the OFDM technique. The slot 1 is a slot usable by the control terminal. The streaming data frame transmitted at this time is represented by 815 in FIG. 8B. Stream data frame 815 is composed of stream data D1 ( 816 ) to D9 ( 824 ) addressed to the respective nodes.

D1 (816) forming part of the stream data frame is stream data addressed to node a 101. Additionally, D2 (817) is stream data addressed to node b 102. D3 (818) is stream data addressed to node c 103. In the same way, D4 (819) to D9 (824) are stream data addressed to nodes d 104 to i 109, respectively. In step S2, the frame configuration of the transmitted stream data frame 815 is communicated to all nodes in advance. Therefore, each node can identify the data portion addressed to itself from among the received flow data frames 815 .

When the stream data frame is transmitted in this way in step S11, the control terminal 110 returns to step S4 again, waits until the start time of the next synchronization period Tf, and repeats the above operation.

Therefore, the control terminal 110 transmits beacon signals ( 811 , 812 , 813 , and 814 ) in each period Tf, and transmits stream data frames ( 815 , 825 , 826 ) through slot 1 ( 803 ) in each period Tf. FIG. 8B shows the transmission operation performed by the control terminal 110 at this time.

node operation

Next, operations of the nodes will be described with reference to FIG. 9 . FIG. 9 is a flowchart showing the processing procedure performed by each node. Note that the description explicitly provided here discusses the case of the operation of node a 101 as an example; however, nodes b 102 to i109 also operate in the same process.

First, single or multiple nodes existing in the surrounding area of node a 101 are detected, and inter-node information necessary for the control terminal 110 to perform a process of determining the node topology is transmitted to the control terminal 110 (step S21) . The process of detecting surrounding nodes by the control terminal 110 will be described in detail later in the description of the process of determining the topology of nodes.

Next, the wireless receiving unit 302 receives control data including information on synchronous communication slot configuration and node group assignment transmitted from the control terminal 110 using the DSSS technique. Node a (101) acquires the slot configuration from the received control data, recognizes the frame configuration of the stream data frame 815, and recognizes the layout of the data D1 (816) addressed to itself. In addition, node a (101) acquires the information of the group to which it belongs based on the received control data, and identifies the slot in which it transmits.

Next, node a (101) judges whether a beacon signal has been received (step S23). In the case of a beacon signal ("No" in step S23), the process proceeds to step S26. In step S24, the cycle timer is restarted. By this restart process (step S24 ), the cycle timer 206 of the control terminal 110 and the cycle timer 307 of the node a ( 101 ) are synchronized, and it becomes possible to determine the cycle Tf and slots 0 to 4 on the node side.

Next, the node a (101) extracts pieces of flow data D1 addressed to itself from among the pieces of flow data frames stored in the memory 304, and sends the flow data D1 to the maximum likelihood processing unit 305; The maximum likelihood processed data is sent to the decoding unit 306, and decoded into AV data (step S25). However, when only a single piece of stream data D1 exists in the memory 304 , the maximum likelihood processing is not performed, and the stream data D1 is sent to the decoding unit 306 . In addition, the received stream data is stored in the memory 304 in step S27, which will be described later.

Next, the node a 101 judges whether or not the wireless receiving unit 302 is receiving streaming data (step S26). In the case of receiving ("Yes" in step S26), the process proceeds to step S27, and in the case of not performing reception ("No" in step S26), the process proceeds to step S28. In step S27 , the wireless receiving unit 302 receives the stream data frame using OFDM technology, and stores the stream data frame in the memory 304 . Here, node a 101 has three receive slots within a single Tf period, namely, slots 1 (803), 3 (805) and 4 (806), which are slots in addition to node a 101's own transmission slots. Therefore, although the process of storing frames of flow data occurs three times within a single Tf period, these frames of flow data are independently stored in the memory 304 and used in the maximum likelihood processing of step S25 described above.

Next, it is judged whether the time indicated by the period timer 307 is the transmission slot of the node itself (step S28 ). If the node belongs to group 1 (112), the transmission slot is slot 2, if the node belongs to group 2 (113), the transmission slot is slot 3, and if the node belongs to group 3 (114), the transmission slot is slot 4. Then, if the current time is the start timing of the transmission slot ("YES" in step S28), the process proceeds to step S29, and in other cases ("NO" in step S28), the process returns to step S23.

In step S29, it is judged whether the group to which the node itself belongs is group 1 (112). In other words, in step S29, it is judged whether the node itself is receiving stream data frames multiple times at the start time of its own transmission slot. In the case where the node belongs to group 1, the stream data frame is directly received from the control terminal 110; therefore, the same data is not being received multiple times, and maximum likelihood processing is not necessary. Conversely, when the node does not belong to group 1, the same data is received multiple times from a plurality of nodes, so maximum likelihood processing must be performed. In the case where it has been judged that the node does not belong to group 1 (112) ("No" in step S29), the process proceeds to step S30; "Yes"), the process goes to step S31.

In step S30, the flow data frame in the memory 304 is sent to the maximum likelihood processing unit 305, and then the flow data frame obtained by performing the maximum likelihood processing is transmitted from the wireless transmission unit 301 using OFDM technology. The stream data frame transmitted at this time is a frame including stream data D1 ( 816 ) to D9 ( 824 ) of all nodes. On the other hand, in step S31 , one of the stream data frames received from the control terminal 110 and within the memory 304 is transmitted as it is from the wireless transmission unit 301 using the OFDM technique.

In the manner described before, when streaming data is transmitted in step S30 or step S31, the node a 101 returns to step S23 again, and repeats the above-described processing. Therefore, each node repeats the following processing within the Tf period: receiving stream data a plurality of times; performing maximum likelihood processing and decoding on data addressed to itself among the received data; and Perform maximum likelihood processing and transfer.

Collaborative operation between control terminals and nodes

10A, 10B, 10C, 10D and 11 show the operations of the control terminal 110 and the nodes 101 to 109 as described above. 10A, 10B, 10C, and 10D are diagrams conceptually showing changes over time in streaming data transmission by the control terminal 110 and nodes. FIG. 11 is a diagram showing streaming data transmission by the control terminal 110 and nodes on the time axis.

First, as shown in FIG. 10A , the control terminal 110 transmits stream data frames within the slot 1 ( 803 ) shown in FIG. 11 . At this time, the signals arriving at nearby nodes a 101, b 102, and c 103 are strong, so stream data frames can be received with a low error rate. However, as the node location becomes farther away, the signal reaching the node becomes weaker, so the distant node receives streaming data frames with a high error rate. The streaming data frame transmitted by the control terminal 110 at this time is a data frame indicated by 815 in FIG. 11 . As shown in FIG. 8B, data frame 815 includes data addressed to all nodes a 101 through i 109.

Next, as shown in FIG. 10B , during slot 2 (804), nodes a 101 to c 103 of group 1 (112) transmit stream data frames. At this time, the signals arriving at nearby nodes d 104 to f 106 are strong, so stream data frames can be received with a low error rate. However, as the node location becomes farther away, the signal reaching the node becomes weaker, so the distant node receives streaming data frames with a high error rate. The stream data frames transmitted by nodes a 101 to c 103 at this time are frame data represented by 901 to 903 in FIG. 11 . In other words, nodes a 101, b 102, and c 103 transmit the data frames they received in slot 1 (803) as they are, thus simultaneously transmitting the same data from the three points. When the same data is simultaneously transmitted from multiple points, as far as the receiving node is concerned, it can be processed in the same way as multi-wave; Unit 626 is used for maximum likelihood processing and estimation of raw data.

Next, as shown in Figure 10C, during slot 3 (805), nodes d 104 to f 106 of group 2 (113) transmit stream data frames. At this time, the signals reaching the nearby nodes a 101 to c 103 and g 107 to i 109 are strong, so stream data frames can be received with a low error rate. However, as the node location becomes farther away, the signal reaching the node becomes weaker, so the distant node receives streaming data frames with a high error rate. At this time, the stream data frames transmitted by nodes d 104 to f 106 are frame data represented by 904 to 906 in FIG. 11 . In other words, nodes d 104 to f 106 perform maximum likelihood processing on the data frames received in slot 1 (803) and slot 2 (804), and transmit the data frames so that the same data. When the same data is simultaneously transmitted from multiple points, as far as the receiving node is concerned, it can be processed in the same way as multi-wave; Unit 626 performs maximum likelihood processing and estimation of the raw data.

Finally, as shown in Figure 10D, during slot 4 (806), nodes g 107 to i 109 of group 3 (114) transmit stream data frames. At this time, the signals arriving at nearby nodes d 104 to f 106 are strong, so stream data frames can be received with a low error rate. However, as the node location becomes farther away, the signal reaching the node becomes weaker, so stream data frames are received with a high error rate. At this time, the stream data frames transmitted by nodes g 107 to i 109 are frame data represented by 907 to 909 in FIG. 11 . In other words, nodes g107 to i109 perform maximum likelihood processing on the data frames received in slot 1 (803), slot 2 (804) and slot 3 (805) and transmit the data frames, thus from the three Points transmit the same data at the same time. When the same data is simultaneously transmitted from multiple points, as far as the receiving node is concerned, it can be processed in the same way as multi-wave; Unit 626 performs maximum likelihood processing and estimation of the raw data.

Through the process, each node receives the same stream data frame from a plurality of nodes and stores the stream data frame in the memory 304 within the repetition period Tf. Then, when the next beacon signal 812 is received, each node extracts a plurality of pieces of data addressed to the node itself from among the plurality of flow data frames stored in the memory 304, through the maximum likelihood processing unit 305 Maximum likelihood processing and reproduction of the original data. The reproduced data is sent to the decoding unit 306 .

Node topology determination processing

Next, the node topology determination process performed by the control terminal 110 in step S1 of FIG. 7 will be described using FIG. 12 . FIG. 12 is a diagram showing the procedure of node topology determination processing by the control terminal and by the nodes. Note that the control terminal 110 and the nodes use the DSSS technique when transmitting/receiving wireless signals in this node topology determination process.

First, the control terminal 110 performs a process of identifying nodes existing in the surrounding area (step S41 ). Nodes are identified by repeating a process in which the control terminal 110 broadcasts an inquiry signal, the nodes receiving the inquiry signal add individual ID values respectively provided to each node in advance to a response signal, and then broadcast the response signal. Nodes randomly change the transmission timing of response signals within a range up to the maximum waiting time Tmax, thereby preventing their response signals from interfering with response signals from other nodes. The control terminal 110 repeatedly transmits the inquiry signal until the response signal stops arriving within the maximum waiting time Tmax, thereby receiving response signals from all nodes. In this way, the control terminal 110 acquires the individual ID values of all the nodes existing in the surrounding area.

Next, the control terminal 110 assigns node numbers corresponding to the number of individual IDs to all the identified nodes, and notifies the nodes of these node numbers (step S42 ). Numbers such as node 1, node 2, and node 3, . . . , node 9 are assigned to the respective nodes a to i in this way.

Next, the control terminal 110 instructs all nodes to start measuring the signal strength of the training signal (step S43 ). All nodes receiving this instruction enter a state in which all nodes measure signal strengths of training signals sequentially transmitted from other nodes including the control terminal, and create a measurement result list (step S50 ).

Then, first, the control terminal 110 starts to transmit the training signal (step S44 ). Note that the training signal has a preset transmission power strength and is transmitted from the control terminal 110 and all nodes with the same signal strength.

Next, the control terminal 110 sequentially requests each node to transmit a training signal with a preset transmission power level (step S45 ). That is, the control terminal 110 sequentially selects each node, and requests the selected node to transmit a training signal. The node receiving the request indication transmits the training signal (steps S51 , S52 and S53 ). During this period, the control terminal 110 measures the signal strength of the training signals transmitted by the respective nodes (step S46 ). Here, as described above, each node is performing the measurement process of the signal strength of the training signal (step S50 ) upon receiving the instruction from the control terminal 110 in step S43 . When the transmission of the training signal has ended with respect to all the nodes, the control terminal 110 then inquires about the respective nodes, and receives a list of measurement results from the respective nodes (step S47 ).

As shown in FIG. 13 , the received signal strength of the training signal received by the control terminal 110 and the nodes is inversely proportional to the distance between the nodes. FIG. 13 is a graph schematically showing the relationship between the strength of the received training signal and the distance between nodes. Therefore, the control terminal 110 is provided with a list of previously measured correspondences between received signal strengths and distances, and then the control terminal 110 determines distances between nodes according to the list of measurement results. If the distance between the nodes can be determined, the positional relationship between the various nodes can be estimated using a known triangulation method such as that shown in FIG. 14 (step S48 ). FIG. 14 is a diagram schematically showing estimation of a positional relationship by triangulation. The distance between the control terminal 110 and the nodes (eg, the distance between the control terminal and nodes a and b) may be estimated based on the training signal received in step S46. In addition, the distance between nodes (eg, the distance between nodes a and b) may be estimated based on the measurements received in step S47 (eg, measurements from nodes a and b).

The control terminal 110 first determines the necessary length of the flow data frame 815 based on the total number of nodes, and then determines the beacon period Tf 801 based on the bit rate of the flow data frame. Then, the control terminal 110 determines the number of groups based on the beacon period Tf, the data frame length, and the total number of nodes. In this way, a time slot configuration such as that shown in FIGS. 8A and 8B is determined; based on the positional relationship between the nodes, adjacent nodes at positions close to the control terminal 110 are configured into the same group; and the layout diagram shown in FIG. 1 is created . Then, according to the layout diagram, determine the group to which the node belongs and the time slot configuration, and communicate the determination result to the node (step S49 ).

In the configuration according to the present embodiment as described above, a plurality of communication terminals constitute a synchronous network; in each synchronization period, a plurality of transmission terminals transmit data of a predetermined length, and a receiving terminal performs maximum approximation on a plurality of received data. Then process, and finally determine (finalize) receive data. Therefore, according to the configuration of this embodiment, a plurality of communication devices redundantly transmit the same data in the same cycle; therefore, abnormalities occurring in a single communication connection are resolved through other communication connections, and the data can be transmitted in the same cycle Transmission to all communication devices. In addition, all terminals are synchronized in time so that transmissions can be avoided from interfering with each other. Therefore, communication can be realized without data disconnection and interruption even when temporally continuous stream data such as video or audio is processed. It is also possible to perform communication in which multiple transmitting terminals simultaneously transmit multiple data streams without interfering with each other.

Example 2

In the foregoing embodiments, nodes belonging to the last group also transmit stream data frames. However, in order to effectively utilize the communication bandwidth, the nodes of the last group may operate not to perform transmission while ensuring redundancy of received data of the respective nodes. For example, in the case where the number of groups is 3, like the first embodiment, slot 4 becomes unnecessary, so the bandwidth used by all nodes within the repetition period Tf can be reduced by not performing communication through slot 4.

In these cases, a method of allocating time slots according to the number of groups can be implemented in the following manner. First, a case where a single group exists will be described. In this case, as shown in Figure 15, all nodes receive data directly from the controlling terminal, so the nodes in group 1 (112) do not need to transmit the received data onwards. Fig. 15 is a diagram schematically showing the configuration of a network when a single group exists. Therefore, only two slots are required, namely, the shared slot, slot 0, and the transmission slot, slot 1. In this case, the redundancy in each node is only 1; however, since the data transmitted from the control terminal 110 is the most correct data, no higher redundancy is required. If a node within a group has poor reception status, the node can be separated into different groups.

Next, a case where there are two groups will be described. In this case, when the nodes of group 2 which is the last group do not transmit, the data path for the nodes to receive is as shown in FIG. 16 . FIG. 16 is a diagram schematically showing the configuration of a network when two groups exist. Nodes in group 1 ( 112 ) only receive transmissions from the control terminal 110 , so their redundancy is one. Nodes in group 2 ( 113 ) receive transmission data from control terminal 110 and transmission data from nodes in group 1 ( 112 ), so their redundancy is two. Therefore, if the nodes of group 2 ( 113 ) transmit onwards, the redundancy of the nodes in group 1 ( 112 ) can be set to 2. At first glance, it would appear pointless to have Group 1 (112) receive transmissions from Group 2 (113). However, due to the transmission by group 2 (113), for example, node a 101 receives data on the direct path from control terminal 110, and receives data on the path from control terminal 110 via node c 103 and node e 105. The data. Therefore, the redundancy of data received from different paths can be set to 2, so that it can be expected to reduce errors by maximum likelihood processing.

The process of determining a group and a time slot (step S49 in FIG. 12 ) by the control terminal 110 performing the above operation will be described in detail with reference to FIG. 17 . FIG. 17 is a flowchart showing a processing procedure performed by the control terminal 110 in this embodiment to determine a group and a time slot.

First, the control terminal 110 finalizes the layout and number of all nodes in the same manner as the processing from step S41 to step S48 in the first embodiment described above (step S61). Then, the control terminal 110 determines the necessary length of the flow data frame 815 based on the total number of nodes, and then determines the beacon period Tf ( 801 ) based on the bit rate of the flow data frame (step S62 ). Then, the control terminal 110 determines the group number N based on the beacon period Tf, the data frame length, and the total number of nodes (step S63 ).

Next, in a case where the number of packets N is 1 (YES in step S64 ), the number of slots into which the period Tf is divided is set to N+1 (step S65 ). In other words, the period Tf is divided into two slots: slot 0, a shared slot; slot 1, a transmission slot for the control terminal 110 . Then, the process goes to step S70.

Next, in a case where the number N of packets is 2 (YES in step S66 ), the number of slots into which the period Tf is divided is set to N+2 (step S67 ). In other words, the period Tf is divided into 4 slots: slot 0, the shared slot; slot 1, the transmission slot of the control terminal 110; slot 2, the transmission slot of group 1; and slot 3, the transmission slot of group 2. Then, the process goes to step S70.

In a case where the number of packets N is 3 or more (YES in step S68 ), the number of slots into which the period Tf is divided is set to N+1 (step S69 ). In other words, the period Tf is divided into N+1 slots: slot 0, the shared slot; slot 1, the transmission slot of the control terminal 110; and slots 2 to N, the transmission slots of groups 1 to (N−1). Then, the process goes to step S70.

In this way, the time slot configuration is determined according to the number of groups N; based on the positional relationship between the nodes, adjacent nodes at positions close to the control terminal 110 are allocated to the same group; and a layout diagram similar to that shown in FIG. 1 is created. Same layout diagram. Then, in step S70, the group to which the node belongs and the time slot configuration are determined according to the layout diagram, and the determination result is communicated to the node.

As previously described, according to the configuration of the present embodiment, groups that do not need to transmit data onward, such as the last group that receives data within each time interval of the repetition cycle, do not communicate. Therefore, according to the configuration of the present embodiment, a longer time interval can be allocated to a group necessary for communication, and thus the data transfer speed can be increased.

Example 3

In the first and second embodiments, the beacon signal is used only as a signal notifying the timing of the repetition period Tf. However, by adding control information to the beacon signal, the control terminal 110 can communicate the timing of each slot, specify the node using the shared slot, and the like.

FIG. 18 is a diagram showing, on the time axis, streaming data transmission by the control terminal 110 and nodes in a case where control information has been added to the beacon signal. In FIG. 18, 921 is the repetition period Tf, 922 is the shared slot, i.e., slot 0, and 923 is the transmission slot of the control terminal 110, i.e., slot 1. 924 to 926 are the transmission slots of groups 1 to 3, respectively, i.e. , slots 2 to 4. 927 to 932 are beacon signals to which control information has been added. 933 is a flow data frame transmitted by the control terminal 110, and 934 to 942 are flow data frames transmitted by nodes a 101 to i 109 respectively.

Information indicating the start of the period Tf and information indicating that the node a 101 is allowed to use the shared slot, that is, slot 0, are added to the beacon signal indicated by 927. At this time, if the node a 101 has information to be conveyed to the control terminal 110, the node a 101 transmits control data. When node a 101 has no information to communicate, node a 101 simply prepares to receive. Nodes b 102 to i 109 are likewise simply ready to receive.

Information indicating that the control terminal 110 has been granted the authority to transport stream data frames is added to the beacon signal indicated by 928 . In response to beacon signal 928 , control terminal 110 transmits stream data frame 933 .

To the beacon signal denoted by 929, information indicating that the authority for the transport stream data frame has been granted to Group 1 is added. Nodes a 101 to c 103 that have received the beacon signal 929 transmit stream data frames 934 to 936.

Information indicating that group 2 has been granted rights to transport stream data frames is added to the beacon signal indicated by 930 . Nodes d 104 to f 106 that have received the beacon signal 930 transmit stream data frames 937 to 939.

To the beacon signal denoted by 931 , information indicating that the authority for the transport stream data frame has been granted to group 3 is added. Nodes g 107 to i 109 receiving the beacon signal 931 transmit stream data frames 940 to 942.

Finally, information indicating the start of the period Tf and information indicating that node b 102 is allowed to use the shared slot, i.e. slot 0, are added to the beacon signal indicated by 932.

In the beacon signal transmitted at the beginning of the period Tf, the information specifying the control terminal 110, the node a 101, the node b 102, the node c 103 to the node i 109 is repeated sequentially as the information of the terminal that is allowed to transmit.

In this way, synchronization between nodes is more easily achieved by relying on the beacon signal to convey the start timing of each slot. In addition, instead of the group number added to the beacon signal, a node number allowed for transmission may be specified. Doing so allows transmission of received data according to the node number specified in the beacon signal even if each node does not know the group it belongs to. Therefore, it can simplify the operation processing of nodes.

Example 4

In the first embodiment, maximum likelihood processing is performed on data simultaneously transmitted from a plurality of nodes in the same manner as regarding multi-way communication by the estimating unit 625 and the equalizing unit 626, and then raw data is estimated. However, the OFDM subchannels may be divided/allocated per transmission node, data may be stored as independent data in the memory 304 of the node at the receiving end, and maximum likelihood processing may be performed by the maximum likelihood processing unit 305.

In this case, for example, the OFDM technique in this embodiment divides communication into 48 sub-channels, and the channels can be allocated to nodes for use as follows:

Channels 1 to 16: node a 101, node d 104 and node g 107;

Channels 17 to 32: node b 102, node e 105 and node h 108;

Channels 33 to 48: node c 103, node f 106 and node i 109.

In this case, for the transmission data sent from the control terminal 110, the same data is redundantly transmitted on channels 1 to 16, 17 to 32, and 33 to 48, respectively.

By using such a configuration, each node can distinguish the transmitting node and receive data; thus the original data can be restored more accurately through maximum likelihood processing.

Example 5

In the above embodiments, it is assumed that the wireless scheme used by the wireless transmission units 201 and 301 and the wireless reception units 202 and 302 is Time Division Multiple Access (TDMA) technology as an example for description. However, the wireless scheme used is not limited thereto. For example, Code Division Multiple Access (CDMA) techniques may be used. In this case, different spreading codes are assigned according to nodes that transmit simultaneously with other nodes, and the wireless transmission units modulate the transmission data using the CDMA technique with the spreading codes assigned to their own nodes, and then transmit the data. On the other hand, the wireless receiving unit has a plurality of spreading code correlation means; by correlating received signals multiple times, signals simultaneously transmitted from a plurality of nodes are divided, received and stored in a memory. Then, the maximum likelihood processing is performed on each received data, and the original data is estimated.

Optionally, the wireless scheme used by the wireless transmission units 201 and 301 and the wireless reception units 202 and 302 may be frequency division multiple access (FDMA) technology. In this case, the transmission frequency is allocated according to the nodes that transmit simultaneously. The wireless receiving unit has multiple receiving units connected in parallel; at the same time, the data received in parallel can be stored in the memory according to the frequency, and the maximum likelihood processing is performed on the received data in the memory, and the original data is estimated.

Optionally, space-division multiple access (SDMA) technology can be used. Alternatively, a combination of the above communication techniques may be used.

In this way, by using wireless technology as necessary, communication suitable for the application and object of communication can be performed.

Example 6

In the described embodiment, the received signal strength of the wireless signal (strength of the signal transmitted from the node) is used to determine the node placement; however, optical devices, acoustic devices or different types of measurement devices may be used or alternatively, these devices combination to determine the layout.

For example, in the case of using an optical device (optical imaging device), the control terminal has a camera and a distance measuring unit for autofocus; nodes are identified by an image captured by the camera, and each node is measured by the distance measuring unit distance. In this way, the controlling terminal can determine the layout of the nodes.

Or, for example, in the case of using an acoustic device, the control terminals and nodes may have speakers for outputting sound waves (acoustic signals) or ultrasonic waves (ultrasonic signals), and microphones for detecting these waves. In this case, the nodes are synchronized with each other; the nodes output sound waves or ultrasonic waves in an order synchronized with the reference time; the distance between nodes is measured based on the amount of delay time (transmission delay) before the sound waves reach the nodes; thus, the control terminal can determine the node Layout. Optionally, because ultrasound has strong directionality, a device that scans the space on the structure can be provided; using known sonar technology, the layout of nodes can be detected by measuring the delay of reflected ultrasound, so that the control terminal can determine the layout of nodes.

Furthermore, a well-known Global Positioning System (GPS) unit may be provided in each node; each node automatically detects its own position and communicates this position to the control terminal so that the control terminal can determine the node layout.

In this way, the node layout can be accurately detected by using optical devices, acoustic devices or different types of measurement devices or, alternatively, a combination of these devices.

Example 7

Although the embodiments of the present invention have been described in detail above, the present invention may take the form of a system, device, program, or storage medium. More specifically, the present invention can be applied to a system including a plurality of devices or to an apparatus including a single device.

It should be noted that there are also cases where the object of the present invention is achieved by directly or remotely providing a program for realizing the functions of the foregoing embodiments to a system or device, and using a computer of the system or device to read the provided program. The program code is then executed.

Therefore, since the functions of the present invention are realized by the computer, the program code itself installed in the computer also falls within the technical scope of the present invention. In other words, the present invention also covers the computer program itself for the purpose of realizing the functions of the present invention.

In this case, the form of the program, such as object code, a program executed by an interpreter, or script data provided to an operating system, does not matter as long as the system or device has the function of the program.

Examples of storage media that can be used to provide the program are floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, magnetic tape, non-volatile memory card, ROM And DVD (DVD-ROM, DVD-R), etc.

Regarding the method of providing the program, the client computer can be connected to a website on the Internet using a browser owned by the client computer, and then the computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded to a record such as a hard disk medium. In addition, the program of the present invention can be provided in such a manner that the program code constituting the program is divided into a plurality of files, and the files are downloaded from different websites. In other words, downloading a program file for realizing the functions of the present invention by a computer to a WWW server of multiple users is also covered by the present invention.

In addition, the program of the present invention can also be encrypted and stored on a storage medium such as a CD-ROM, and then, the storage medium is distributed to users, allowing users who meet certain requirements to download decryption key information from a website through the Internet , and allow those users to install the program on the user's computer by decrypting the encrypted program using the key information. Furthermore, except for the case where the aforementioned functions according to the embodiments are realized by the computer executing the read program, an operating system or the like running on the computer may perform all or part of the actual processing so that the aforementioned embodiments can be realized by the processing. Function.

In addition, after writing the program read from the storage medium into the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, the CPU etc. mounted on the function expansion board or the function expansion unit performs all Or part of the actual processing, so that the functions of the foregoing embodiments can be realized through this processing.

In this way, according to the above-described embodiments, it is possible to provide a technique for reducing the occurrence of disconnection or interruption when transmitting/receiving temporally continuous streaming data such as video or audio. Furthermore, it is possible to provide a technique for avoiding mutual interference even when a plurality of pieces of data are simultaneously transmitted to a plurality of reception terminals.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be accorded the broadest interpretation to encompass all such modifications and equivalent structures and functions.

Claims (22)

1. A control device that communicates with a plurality of communication devices, the control device comprising: An allocating unit configured to perform the following operations respectively: allocating a first communication slot to the first communication device and the second communication device to directly receive data from the sender communication device; and allocating a second communication slot to the second communication device to receive The data that has been directly received by the first communication device from the sender communication device and subjected to relay transmission processing; and A notification unit, configured to notify each of the plurality of communication devices of the configuration of the communication slot allocated by the allocation unit. 2. The control device according to claim 1, further comprising a division unit configured to divide the plurality of communication devices into groups, Wherein, the division unit divides the first communication device and the second communication device into different groups, and The notification unit also notifies each of the plurality of communication devices of the group to which the communication device belongs. 3. The control device according to claim 1 or 2, further comprising a transmission unit configured to transmit data to the plurality of communication devices according to a predetermined timing. 4. The control device according to claim 3, wherein the transmission unit transmits the data using time division multiple access, code division multiple access, frequency division multiple access and/or space division multiple access techniques. 5. The control device according to claim 3, characterized in that the notification unit and the transmission unit utilize different modulation techniques. 6. The control device according to claim 2, further comprising a determining unit configured to determine a relative position of each of the plurality of communication devices, Wherein, the division unit divides the plurality of communication devices into groups based on the determination performed by the determination unit. 7. The control device according to claim 6, wherein the determination unit is based on the strength of a transmission signal from each of the plurality of communication devices, a transmission delay of an acoustic signal or an ultrasonic signal, or optical imaging The optical imaging results of the unit are used for determination. 8. The control device according to any one of claims 2, 6 and 7, characterized in that the distribution units are arranged in order from the group at the closest position to the control device at the farthest position from the control device The order of the group of positions to allocate the communication slots. 9. The control device according to claim 8, wherein the distribution unit performs the following operations: When the number of groups divided by the dividing unit is 1, no communication slot is allocated to the group; In the case where the number of groups into which the dividing unit is divided is 2, allocating a communication slot to each of all the groups; and In a case where the number of groups into which the dividing unit is divided is 3 or more, no communication slot is allocated to the group at the farthest position from the control device. 10. The control device of claim 1, wherein the data includes data of each of the plurality of communication devices. 11. The control device according to claim 1, wherein the sender communication device is the control device. 12. A communication device comprising: a receiving unit for receiving data in each of a plurality of communication slots, wherein the receiving unit receives data that has been directly transmitted from a first other communication device in a first communication slot, and in a second communication slot receiving data that has been directly received by the second other communication device from the first other communication device and subjected to relay transmission processing; and A generating unit configured to generate output data based on the data received by the receiving unit in the first communication slot and the second communication slot. 13. The communication device according to claim 12, further comprising: a first maximum likelihood unit, configured to perform maximum likelihood processing on data received in the plurality of communication slots; and A transmission unit, configured to transmit the data on which the maximum likelihood processing has been performed by the first maximum likelihood unit to other communication devices. 14. The communication device according to claim 13, further comprising an acquisition unit configured to acquire a communication slot assigned to the communication device and for which the communication device transmits data, and The transmission unit transmits the data that has been subjected to maximum likelihood processing by the first maximum likelihood unit to other communication devices within a communication slot allocated to the communication device. 15. The communication device according to claim 14, wherein the obtaining unit further obtains a group to which the communication device belongs. 16. A communications device according to any one of claims 12 to 15, wherein The data received by the receiving unit includes data of each of a plurality of communication devices, and The communication device further includes a readout unit, which is used to read data for the communication device from the data received by the receiving unit. 17. The communication device according to claim 16, further comprising a second maximum likelihood unit, the second maximum likelihood unit is used to analyze the readout unit from the first communication slot performing maximum likelihood processing on the data for the communication device read from the data respectively received in the second communication slot, and The generating unit generates the output data by decoding the data on which the second maximum likelihood unit has subjected the maximum likelihood processing. 18. The communication device according to claim 13, wherein the receiving unit and the transmitting unit communicate using time division multiple access, code division multiple access, frequency division multiple access and/or space division multiple access techniques . 19. The communication device according to claim 12, further comprising a control unit configured to generate information for estimating a distance to the other communication device based on communication with the other communication device, and The transmission of this information to the control device is controlled in response to a request from the control device of the system to which the communication device belongs. 20. A communication system comprising a control device and a plurality of communication devices, Wherein, the control equipment includes: An allocating unit configured to perform the following operations respectively: allocating a first communication slot to the first communication device and the second communication device to directly receive data from the sender communication device; and allocating a second communication slot to the second communication device to receive The data that has been directly received by the first communication device from the sender communication device and subjected to relay transmission processing; and a notification unit configured to notify each of the plurality of communication devices of the configuration of the communication slot allocated by the allocation unit, and The communication equipment includes: a receiving unit for receiving data in each of a plurality of communication slots, wherein the receiving unit receives data that has been directly transmitted from a first other communication device in a first communication slot, and in a second communication slot receiving data that has been directly received by the second other communication device from the first other communication device and subjected to relay transmission processing; and A generating unit configured to generate output data based on the data received by the receiving unit in the first communication slot and the second communication slot. 21. A control method for a control device, the control device communicates with a plurality of communication devices, the control method comprising the following steps: an allocating step for respectively performing the following operations: allocating a first communication slot to the first communication device and the second communication device to directly receive data from the sender communication device; and allocating a second communication slot to the second communication device to receive The data that has been directly received by the first communication device from the sender communication device and subjected to relay transmission processing; and Notifying each of the plurality of communication devices of the configuration of the communication slot allocated in the allocating step. 22. A method for controlling a communication device, comprising the following steps: a receiving step for receiving data in each of a plurality of communication slots, wherein the receiving step receives data that has been directly transmitted from a first other communication device in a first communication slot, and in a second communication slot receiving data that has been directly received by the second other communication device from the first other communication device and subjected to relay transmission processing; and Output data is generated based on the data received in the first communication slot and the second communication slot in the receiving step.

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